1. Field of the Invention
The present invention relates to a stereoscopic display device, and more particularly, to an electrically-driven liquid crystal lens wherein electric connection between finely split electrodes and signal lines used to apply signals to the split electrodes can be accomplished using a minimal number of masks and wherein signals can be applied to the finely split electrodes without the effect of line resistance, and a stereoscopic display device using the same.
2. Discussion of the Related Art
At present, services for rapid dissemination of information, constructed on the basis of high-speed information communication networks, have developed from a simple “listening and speaking” service, such as current telephones, to a “watching and listening” multimedia type service on the basis of digital terminals used for high-speed processing of characters, voice and images, and are expected to be ultimately developed into cyberspace 3-dimensional stereoscopic information communication services enabling virtual reality and stereoscopic viewing free from the restrains of time and space.
In general, stereoscopic images representing 3-dimensions are realized based on the principle of stereo-vision via the viewer's eyes. However, since the viewer's eyes are spaced apart from each other by about 65 mm, i.e. have a binocular parallax, the left and right eyes perceive slightly different images due to a positional difference therebetween. Such a difference between images due to the positional difference of the eyes is called binocular disparity. A 3-dimensional stereoscopic image display device is designed on the basis of binocular disparity, allowing the left eye to view only an image for the left eye and the right eye to view only an image for the right eye.
Specifically, the left and right eyes view different 2-dimensional images, respectively. If the two different images are transmitted to the brain through the retina, the brain accurately fuses the images, giving the impression of real 3-dimensional images. This ability is conventionally called stereography.
Technologies for displaying the above-described 3-dimensional stereoscopic images may be classified into a stereoscopic display type, volumetric measurement type, and hologram type. Of these types, the stereoscopic display type may be classified into two types, one using 3D glasses and the other not using glasses. In turn, the type not using glasses may be classified, based on the shape of a structure used for 3D realization, into a parallax barrier type and a lenticular type. A discussion of lenticular type stereoscopic displays follows.
Hereinafter, a conventional lenticular type stereoscopic liquid crystal display device will be described with reference to the drawings.
FIG. 1 is a perspective view illustrating a conventional lenticular type stereoscopic liquid crystal display device, and FIG. 2 is a sectional view illustrating the stereoscopic liquid crystal display device of FIG. 1.
As shown in FIG. 1, the conventional lenticular type stereoscopic liquid crystal display device includes a liquid crystal panel 10 consisting of upper and lower substrates 10a and 10b with liquid crystals 10c filled therebetween, a backlight unit 20 located at a back surface of the liquid crystal panel 10 and serving to direct light toward the liquid crystal panel 10, and a lenticular plate 30 located at a front surface of the liquid crystal panel 10 and serving to realize stereoscopic images.
As shown in FIG. 2, first and second polarizers 11 and 12 are attached to an upper surface of the upper substrate 10a and a lower surface of the lower substrate 10b, respectively.
The lenticular plate 30 is fabricated by forming a material layer, having a convex-lens-shaped upper surface, on a flat substrate.
When images, having passed through the liquid crystal panel 10, exit the lenticular plate 30, the viewer's eyes perceive different groups of images, whereby 3-dimensional stereoscopic images can be realized.
In the above-described conventional stereoscopic liquid crystal display device, the lenticular plate 30 and liquid crystal panel 10 are supported by structures (not shown), and the first polarizer 11 on the liquid crystal panel 10 is spaced apart from the lenticular plate 30 by a predetermined distance.
With this configuration, however, the liquid crystal panel 10 or the lenticular plate 30 may droop or bend into a space between the first polarizer 11 on the liquid crystal panel 10 and the lenticular plate 30. This bending phenomenon results in abnormal optical pathways through the backlight unit 20, liquid crystal panel 10, and lenticular plate 30, thereby deteriorating image quality.
To reduce the space between the liquid crystal panel 10 and the lenticular plate 30, inserting an adhesive between the liquid crystal panel 10 and the lenticular plate 30 to attach the liquid crystal panel 10 and lenticular plate 30 to each other might be considered. However, the greater the area of the liquid crystal panel 10, the greater the required amount of the adhesive. Moreover, the adhesive problematically causes deterioration in transmissivity.
Other problems associated with the attachment of the above-described lenticular lens include the use of the adhesive, deteriorated visual sensitivity due to the bending phenomenon, or a difficulty in the processing of a smooth lenticular lens.
For these reasons, in lieu of rounding a lens plane to a convex plane, there has been introduced an electrically-driven liquid crystal lens wherein liquid crystals, filled between upper and lower substrates, undergo a difference in optical pathways thereof depending on an electric potential plane when an electric field is applied to the liquid crystals.
In the above-described electrically-driven liquid crystal lens, however, due to line resistance induced by line-shaped electrodes, the greater the size of the electrically-driven liquid crystal lens, the greater the probability of a difference in voltages applied to upper and lower ends of the electrically-driven liquid crystal lens.
Further, when arranging electrodes in two layers, processes for forming contacts between electrodes and signal lines of the respective layers are required. This increases the number of masks used and consequently, the number of corresponding exposure and developing processes, resulting in deterioration in production yield.